Effective grazing management reduces the exposure of sheep to worms. There are three methods:
The last two are used to prepare ‘low worm-risk’ paddocks for lambing ewes and weaners.
Ewes temporarily lose some of their immunity to worms at and after lambing. As a result, they contribute greatly to the seasonal increase in worm numbers and subsequent infection of lambs.
Weaners are also highly susceptible to worms. Low worm-risk weaning paddocks give weaners a good start so they can build immunity without suffering high initial infections.
Whether the paddock is for lambing ewes or for weaned lambs the method of preparation is the same. However, the length of preparation will vary according to the time of the year the paddock first needs to be used. Refer to Table 1 (below) to find out how long you need to prepare your paddock.
Preparation: In the months (see Table 1 below) before it is required for use as a lambing or weaning paddock, prevent contamination of the paddock with sheep worm eggs by any combination of these:
Table 1. Months of preparation required for low worm-risk paddocks
|The first month weaning or lambing starts||Eastern areas of this worm control region*||Western areas of this worm control region**|
|July, August, September or October||5||4|
|November or December||4||3|
|January, February, March or April||3||2|
|May or June||4||3|
* includes towns such as Narrabri, Moree, Warwick and Dalby
** includes towns such as Nyngan, Walgett, St George and Mitchell
Rotational grazing with short graze periods alternated with rest periods can greatly reduce the number of worm larvae on pasture, especially barber’s pole worm. While these systems (e.g. planned grazing, cell grazing, techno-grazing and intensive rotational grazing) are outside the scope of this publication, and may not be applicable to producers in this region, they use the principles found in Factors contributing to paddock contamination with worms.